Sakuranin Is a Novel Anti-Inflammatory Agent Targeting TLR4-NF-κB Signaling Pathways

Sakuranin (SKR) is naturally occurring compound known for its anti-inflammatory and antioxidant activities; however, its precise molecular mechanisms in modulating inflammation through toll-like receptor 4 (TLR4) signaling remain unclear. This study investigates the anti-inflammatory effects of SKR in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and zebrafish larvae, focusing on the TLR4-nuclear factor-kappa B (NF-κB) signaling pathway. SKR significantly inhibited the production of nitric oxide (NO), prostaglandin E₂ (PGE₂), interleukin-12 (IL-12), and tumor necrosis factor-alpha (TNF-α), while downregulating the expression of inducible NO synthase (NOS2) and cyclooxygenase-2 (COX2) at both transcriptional and translational levels. In vivo, SKR reduced LPS-induced mortality, restored cardiac function, and attenuated immune cell infiltration in zebrafish larvae, further underscoring its systemic anti-inflammatory effects. Mechanistic studies revealed that SKR inhibited NF-κB nuclear translocation and directly interacted with the TLR4/myeloid differentiation factor 2 (MD2) complex, thereby disrupting LPS-TLR4 signaling. Molecular docking and colocalization analyses confirmed that SKR directly binds TLR4, potentially interfering with LPS recognition and downstream pro-inflammatory signaling activation. Collectively, these findings highlight SKR as a potent modulator of TLR4-mediated inflammation, offering promising therapeutic potential for inflammatory disorders. Further investigations into its pharmacokinetics, bioavailability, and long-term efficacy in chronic inflammatory conditions are warranted to support its clinical applications.